CN205105094U - Promote buck output voltage's circuit - Google Patents
Promote buck output voltage's circuit Download PDFInfo
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- CN205105094U CN205105094U CN201520840296.8U CN201520840296U CN205105094U CN 205105094 U CN205105094 U CN 205105094U CN 201520840296 U CN201520840296 U CN 201520840296U CN 205105094 U CN205105094 U CN 205105094U
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Abstract
The utility model provides a promote buck output voltage's circuit, including the power end, connect gradually switch tube and the first loop, second return circuit and load at the power end. The power end provides input voltage through positive bus -bar and negative busbar for the circuit. The first loop includes first electric capacity, first inductance and a freewheeling diode, and when the switch tube switched on, input voltage charged to first inductance through first electric capacity, and when the switch tube ended, first inductance discharged through a first electric capacity and a freewheeling diode. The second return circuit includes the second inductance with first inductance phase coupling, and with second electric capacity and the 2nd freewheeling diode that the second inductance looped in, second electric capacity and first electric capacity are established ties, ends at the switch tube, and when first inductance discharged, the second inductance produced coupling voltage and discharges through the second return circuit. The load is connected between the negative terminal of the anode of first electric capacity and second electric capacity.
Description
Technical field
The utility model relates to a kind of buck circuit, and in particular to a kind of circuit promoting buck output voltage.
Background technology
LED illumination, due to outstanding energy-efficient performance, has obtained applying more and more widely.In order to meet the network operation voltage of country variant, simultaneously inputting the capacitive filter harmonic pollution serious to electrical network to prevent, requiring, within the scope of whole Width funtion input 100 ~ 264Vac, all there is good constant current effect, possess High Power Factor and current harmonics meets corresponding harmonic standard.
In order to meet the humorous requirement involving High Power Factor, LED drive power needs circuit of power factor correction usually.Traditional circuit of power factor correction generally adopts boosting (Boost) circuit, but usually output voltage is too high cannot be suitable for.Therefore, in recent years, the circuit of power factor correction of voltage-dropping type is adopted, as buck circuit.The method of existing Buck circuit realiration Active PFC has two kinds: a kind of is that the constant turn-on time being operated in critical continuous conduction mode controls, and another kind is the peak value comparison method being operated in critical continuous conduction mode.Two kinds of control modes can meet corresponding harmonic standard in the application of low output voltage.
But in high output voltage application scenario, due to the restriction of the operation principle of buck circuit own, namely require that input voltage must be greater than output voltage buck circuit and just can normally work.Now the angle of flow of a power frequency period can diminish gradually along with uprising of output voltage, and as shown in Figure 1, along with being increased in a power frequency period of output voltage, the angle of flow reduces gradually.The reduction of the angle of flow will cause Harmonics of Input to uprise, and be difficult to the standard meeting current harmonics.
Utility model content
The utility model is in order to overcome the increase of existing buck circuit along with output voltage, in a power frequency period, the angle of flow reduces thus the problem that Harmonics of Input is uprised, and provides a kind of circuit that can increase the lifting buck output voltage of the angle of flow in a power frequency period while improving output voltage.
To achieve these goals, the utility model provides a kind of circuit promoting buck output voltage, comprises power end, is connected to switching tube and the first loop, second servo loop and the load of power end in turn.Power end through positive bus-bar and negative busbar for circuit provides input voltage.First loop comprises the first electric capacity, the first inductance and the first fly-wheel diode, and when switching tube conducting, input voltage charges to the first inductance through the first electric capacity, and when switching tube ends, the first inductance discharges through the first electric capacity and the first fly-wheel diode.Second servo loop comprises the second inductance be coupled with the first inductance, form the second electric capacity and second fly-wheel diode in loop with the second inductance, the second electric capacity and the first capacitances in series, end at switching tube, during the first inductive discharge, the second inductance produces coupled voltages and discharges through second servo loop.Load is connected between the anode of the first electric capacity and the negative terminal of the second electric capacity.
In the utility model one embodiment, first inductance discharge time to the first capacitor charging, the voltage at the first electric capacity two ends and the number of turn N1 of the first inductance proportional, second inductance discharge time to the second capacitor charging, the voltage at the second electric capacity two ends and the number of turn N2 of the second inductance proportional, the number of turn N1 of the first inductance is greater than the number of turn N2 of the second inductance.
In the utility model one embodiment, switching tube is connected with the negative busbar of circuit, and the first fly-wheel diode Opposite direction connection is between positive bus-bar and switching tube.
In the utility model one embodiment, switching tube adopts and drives floatingly, and switching tube is connected with the positive bus-bar of circuit, and the first fly-wheel diode Opposite direction connection is between switching tube and negative busbar.
In the utility model one embodiment, the first electric capacity and the second electric capacity are electrochemical capacitor.
In the utility model one embodiment, the circuit promoting buck output voltage also comprises and is arranged on power end and bridge rectifier input voltage being carried out to rectification.
In the utility model one embodiment, switching tube is MOSFET.
In sum, the circuit of the lifting buck output voltage that the utility model provides compared with prior art, has the following advantages:
In switching tube conduction period, input voltage to the first induction charging, and in the second loop due to the second fly-wheel diode cut-off, does not have electric current to flow through through loop that the first electric capacity, the first inductance and switching tube form in second servo loop.When switching tube cut-off, the first inductance, by the first loop electric discharge of the first electric capacity, the first inductance and the first fly-wheel diode composition, simultaneously the second inductance produces coupled voltages, and this coupled voltages is through the second electric capacity and the electric discharge of the second fly-wheel diode.When switching tube conducting, say from input side, the angle of flow in a power frequency period determined by the voltage on the first electric capacity.Because output voltage is the voltage on the first electric capacity and the voltage sum on the second electric capacity, therefore, can show that the voltage on the first electric capacity is less than output voltage.Relation according to voltage and the angle of flow can obtain, the utility model provides buck circuit with coupling inductance compared with traditional buck circuit, when output voltage is identical, only determine, in a power frequency period, there is the larger angle of flow by the voltage on the first electric capacity at the input side angle of flow.The increase of the angle of flow effectively can improve the sine degree of electric current, reduces current harmonics.
For above-mentioned and other objects, features and advantages of the present utility model can be become apparent, preferred embodiment cited below particularly, and coordinate accompanying drawing, be described in detail below.
Accompanying drawing explanation
Figure 1 shows that the graph of a relation of input voltage, output voltage and the angle of flow in traditional buck circuit.
Figure 2 shows that the schematic diagram of the circuit of the lifting buck output voltage that the utility model one embodiment provides.
Figure 3 shows that the graph of a relation of input voltage, output voltage and the angle of flow in the circuit of the lifting buck output voltage shown in Fig. 2.
Figure 4 shows that the schematic diagram of the circuit of the lifting buck output voltage that another embodiment of the utility model provides.
Embodiment
Principle by buck circuit limits, and it requires that input voltage must be greater than output voltage.As shown in Figure 1, Vin (t) is input voltage, Vo is output voltage, in the scope of θ ~ п-θ, buck circuit normally works, wherein θ is the initial angle that buck circuit normally works, and п-θ is the end angle that buck circuit normally works, and п-2 θ is the angle of flow that buck circuit normally works.As can be seen from Figure 1, along with the continuous rising of output voltage, the value of initial angle θ can constantly increase, and accordingly, angle of flow п-2 θ will significantly reduce.In the circuit of this kind of topological structure, the reduction of the angle of flow will make the harmonic wave of input current increase, and is finally difficult to satisfied corresponding harmonic standard.
In view of this, for solving this problem, the present embodiment provides a kind of circuit promoting buck output voltage, comprises power end, is connected to switching tube Q and the first loop, second servo loop and the load R of power end in turn.Power end through positive bus-bar and negative busbar for circuit provides input voltage.First loop comprises the first electric capacity C1, the first inductance L 1 and the first sustained diode 1, and when switching tube Q conducting, input voltage charges to the first inductance L 1 through the first electric capacity C1.When switching tube Q ends, the first inductance L 1 is discharged through the first electric capacity C1 and the first sustained diode 1.Second servo loop comprises the second inductance L 2 be coupled with the first inductance L 1, the second electric capacity C2 and second sustained diode 2 in loop is formed with the second inductance L 2, second electric capacity C2 connects with the first electric capacity C1, end at switching tube Q, when first inductance L 1 is discharged, the second inductance L 2 produces coupled voltages and discharges through second servo loop.Load R is connected between the anode of the first electric capacity C1 and the negative terminal of the second electric capacity C2.
First loop is identical with the structure of traditional buck circuit with the structure of switching tube, the second servo loop that the second inductance L 2 that the present embodiment increases coupling on the basis of traditional buck circuit forms.In switching tube Q conduction period, the input voltage of interchange charges to the first inductance L 1 through the first electric capacity C1, and the second sustained diode 2 now in second servo loop is cut-offs, no current in the second inductance L 2.Now, be determined by the voltage U c1 the first electric capacity C1 from the work angle of flow of buck circuit viewed from input side.
First inductance L 1 is while discharging by the first loop, and due to electromagnetic field couples, the second inductance L 2 can produce coupled voltages, this coupled voltages discharges through the second electric capacity C2 and the second sustained diode 2, charges to the second electric capacity C2.Because the first electric capacity C1 and the second electric capacity C2 connect and load R is connected between the anode of the first electric capacity C1 and the negative terminal of the second electric capacity C2, namely the output voltage Vo outputted on load R is the voltage U c1 on the first electric capacity C1 and the voltage U c2 sum on the second electric capacity, i.e. Vo=Uc1+Uc2.Can find out that Uc1 certainly will be less than Vo from this relation.In the circuit of the lifting buck output voltage provided at the utility model, the work angle of flow of buck circuit is determined by the voltage U c1 on the first electric capacity C1, and Uc1 is less than Vo.Therefore, composition graphs 1 can obtain with Fig. 3: compared with traditional buck circuit, and when output voltage Vo is identical, the circuit of the lifting buck output voltage that the utility model provides has the larger angle of flow.In other words, when the angle of flow is identical, the circuit of the lifting buck output voltage that the application provides can have higher output voltage Vo.In Fig. 3, θ 1 is the initial angle that the circuit promoting buck output voltage normally works, and п-θ 1 is the end angle that the circuit promoting buck output voltage normally works.
When switch Q ends, the voltage U 1 at the first inductance L 1 two ends differs the conducting voltage of first sustained diode 1 with the voltage U c1 on the first electric capacity C1.The conducting voltage of the first sustained diode 1 is very little, can be similar to think U1=Uc1.Identical, when the generation coupled voltages in the second inductance L 2 and when discharging, the voltage U 2 at the second inductance L 2 two ends differs the conducting voltage of second sustained diode 2 with the voltage U c2 on the second electric capacity C2.The conducting voltage of the second sustained diode 2 is very little, can be similar to think U2=Uc2.According to the voltage relationship U1:U2=N1:N2 between coupling inductance, i.e. Uc1:Uc2=N1:N2.According to the control of circuit by regulating the number of turn N2 of the number of turn N1 of the first inductance L 1 and the second inductance L 2 to realize Uc1 and Uc2 of the lifting buck output voltage that this relation the present embodiment provides.
Can draw from Vo=Uc1+Uc2, Uc1 value less (namely the number of turn N1 of the first inductance is less), the circuit of the lifting buck output voltage that the utility model provides has the larger angle of flow, can reduce the harmonic content of input current further.But in actual use, too low Uc1 value will make circuit working unstable.In view of this, the number of turn N1 that the present embodiment arranges the first inductance is greater than the number of turn N2 of the second inductance.But the utility model is not limited in any way this.
In the present embodiment, switching tube Q is MOSFET, and the first electric capacity C1 and the second electric capacity C2 is electrochemical capacitor.But the utility model is not limited in any way this.In other embodiment, switching tube Q can be the metal-oxide-semiconductor of triode or other type, and the first electric capacity C1 and the second electric capacity C2 can be the capacitor of other types such as air dielectric capacitor.
In the present embodiment, for ease of the driving of switching tube Q, arrange switching tube Q and be connected with the negative busbar of circuit, the first sustained diode 1 Opposite direction connection is between positive bus-bar and switching tube Q.In this kind of structure, because the source electrode of switching tube Q is connected with negative busbar, the V of switching tube Q
gSfixing, switching tube Q, without the need to adopting floating driving, enormously simplify the project organization of circuit.But the utility model is not done any to this.In other embodiment, as shown in Figure 4, switching tube Q can be connected with the positive bus-bar of circuit, and now the first sustained diode 1 Opposite direction connection is between switching tube and positive bus-bar.In this kind of connected mode, the source electrode of switching tube Q is connected with the negative pole of the first sustained diode 1, the V of switching tube Q
gSdo not fix, need employing to drive floatingly.
In the present embodiment, the circuit promoting buck output voltage also comprises and is arranged on power end and bridge rectifier D input voltage being carried out to rectification.
In sum, in switching tube conduction period, input voltage to the first induction charging, and in the second loop due to the second fly-wheel diode cut-off, does not have electric current to flow through through loop that the first electric capacity, the first inductance and switching tube form in second servo loop.When switching tube cut-off, the first inductance, by the first loop electric discharge of the first electric capacity, the first inductance and the first fly-wheel diode composition, simultaneously the second inductance produces coupled voltages, and this coupled voltages is through the second electric capacity and the electric discharge of the second fly-wheel diode.When switching tube conducting, say from input side, the angle of flow in a power frequency period determined by the magnitude of voltage of the first electric capacity.Because output voltage is the voltage on the first electric capacity and the voltage sum on the second electric capacity, therefore, can show that the voltage on the first electric capacity is less than output voltage.Relation according to voltage and the angle of flow can obtain, the utility model provides buck circuit with coupling inductance compared with traditional buck circuit, when output voltage is identical, only determine, in a power frequency period, there is the larger angle of flow by the voltage on the first electric capacity at the input side angle of flow.The increase of the angle of flow effectively can improve the sine degree of electric current, reduces current harmonics.
Although the utility model discloses as above by preferred embodiment; but and be not used to limit the utility model; anyly know this those skilled in the art; not departing from spirit and scope of the present utility model; can do a little change and retouching, therefore protection range of the present utility model is when being as the criterion depending on claims scope required for protection.
Claims (7)
1. promote a circuit for buck output voltage, it is characterized in that, comprising:
Power end, through positive bus-bar and negative busbar for circuit provides input voltage;
Be connected to switching tube and first loop of power end in turn, described first loop comprises the first electric capacity, the first inductance and the first fly-wheel diode, when switching tube conducting, input voltage charges to the first inductance through the first electric capacity, when switching tube ends, the first inductance discharges through the first electric capacity and the first fly-wheel diode;
Second servo loop, comprises the second inductance be coupled with described first inductance, forms the second electric capacity and second fly-wheel diode in loop with the second inductance, second electric capacity and the first capacitances in series, in switching tube cut-off, during the first inductive discharge, the second inductance produces coupled voltages and discharges through second servo loop;
Load, is connected between the anode of the first electric capacity and the negative terminal of the second electric capacity.
2. the circuit of lifting buck output voltage according to claim 1, it is characterized in that, first inductance discharge time to the first capacitor charging, the voltage at the first electric capacity two ends and the number of turn N1 of the first inductance proportional, second inductance discharge time to the second capacitor charging, the voltage at the second electric capacity two ends and the number of turn N2 of the second inductance proportional, the number of turn N1 of the first inductance is greater than the number of turn N2 of the second inductance.
3. the circuit of lifting buck output voltage according to claim 1, it is characterized in that, described switching tube is connected with the negative busbar of circuit, and the first fly-wheel diode Opposite direction connection is between positive bus-bar and switching tube.
4. the circuit of lifting buck output voltage according to claim 1, it is characterized in that, described switching tube adopts and drives floatingly, and switching tube is connected with the positive bus-bar of circuit, and the first fly-wheel diode Opposite direction connection is between switching tube and negative busbar.
5. the circuit of lifting buck output voltage according to claim 1, it is characterized in that, described first electric capacity and the second electric capacity are electrochemical capacitor.
6. the circuit of lifting buck output voltage according to claim 1, is characterized in that, the circuit of described lifting buck output voltage also comprises and is arranged on power end and bridge rectifier input voltage being carried out to rectification.
7. the circuit of lifting buck output voltage according to claim 1, it is characterized in that, described switching tube is MOSFET.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520840296.8U CN205105094U (en) | 2015-10-27 | 2015-10-27 | Promote buck output voltage's circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520840296.8U CN205105094U (en) | 2015-10-27 | 2015-10-27 | Promote buck output voltage's circuit |
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| Publication Number | Publication Date |
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| CN205105094U true CN205105094U (en) | 2016-03-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520840296.8U Active CN205105094U (en) | 2015-10-27 | 2015-10-27 | Promote buck output voltage's circuit |
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| CN (1) | CN205105094U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105207472A (en) * | 2015-10-27 | 2015-12-30 | 杰华特微电子（杭州）有限公司 | Circuit used for boosting buck output voltage |
| CN105871206A (en) * | 2016-05-20 | 2016-08-17 | 中国矿业大学 | Improved Buck converter based on pulse sequence control |
-
2015
- 2015-10-27 CN CN201520840296.8U patent/CN205105094U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105207472A (en) * | 2015-10-27 | 2015-12-30 | 杰华特微电子（杭州）有限公司 | Circuit used for boosting buck output voltage |
| CN105871206A (en) * | 2016-05-20 | 2016-08-17 | 中国矿业大学 | Improved Buck converter based on pulse sequence control |
| CN105871206B (en) * | 2016-05-20 | 2018-12-14 | 中国矿业大学 | A kind of improved B uck converter based on pulse train control |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee after: Jiehuate Microelectronics Co.,Ltd. Address before: Room 424, building 1, 1500 Wenyi West Road, Cangqian street, Yuhang District, Hangzhou City, Zhejiang Province Patentee before: JOULWATT TECHNOLOGY (HANGZHOU) Co.,Ltd. |
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| CP03 | Change of name, title or address |